P53 IMMUNOHISTOCHEMISTRY IN TRANSITIONAL-CELL CARCINOMA AND DYSPLASIAOF THE URINARY-BLADDER CORRELATES WITH DISEASE PROGRESSION

Immunohistochemically detectable p53 protein using a polyclonal antibo dy (CM-1) was studied in 42 carcinomas of which 11 were grade 1, 22 gr ade II and nine grade III carcinomas. Additionally 14 urothelial dyspl asias were studied. In 11 of these a diagnosis of transitional cell ca rcinoma was established before and in one after the dysplasia diagnosi s. Twenty-one out of 42 (50%) cases of transitional cell carcinoma wer e positive for the p53 protein. Eleven out of 14 (78%) dysplasias and 10/12 (83%) related carcinomas were p53 positive. One out of 11 grade I (9%), 12/22 grade II (55%) and 8/9 grade III (89%) tumours showed po sitivity for p53. There were significantly more p53 positive cases in grade II-III tumours than in grade I tumours (P = 0.004). There were s ignificantly more p53 positive cases in stage T2-T4 tumours than in st age T1 tumours (P = 0.035). In only one case among the 11 dysplastic l esions following the treatment of a carcinoma the dysplastic lesion wa s p53 negative while the preceding carcinoma was p53 positive. All dys plasias and 28 carcinomas were also immunostained for laminin and type IV collagen to evaluate the continuity of basement membranes (BMs). C learly disrupted BMs were observed only in grade III carcinomas. These cases showed the most p53 immunopositivity. The results show a strong association of p53 staining between dysplasias and transitional cell carcinomas of the urinary bladder indicating that these lesions might share similar p53 changes. The correlation to grade, clinical stage an d to disrupted BM suggests that p53 mutations may be associated with t he evolution of aggressive growth characteristics in transitional cell carcinomas or, alternatively, that p53 positive tumours of a more agg ressive type from the start. Whether p53 staining can be used as an ad junct in the assessment and follow-up of epithelial changes of patient s treated for a p53 positive bladder carcinoma deserves to be studied.